/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
 * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 * Sun designates this particular file as subject to the "Classpath" exception
 * as provided by Sun in the GPL Version 2 section of the License file that
 * accompanied this code.  If applicable, add the following below the License
 * Header, with the fields enclosed by brackets [] replaced by your own
 * identifying information: "Portions Copyrighted [year]
 * [name of copyright owner]"
 *
 * Contributor(s):
 *
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

/*
 * @(#)FileTypeMap.java	1.9 07/05/14
 */

package javax.activation;

import java.io.File;

/**
 * The FileTypeMap is an abstract class that provides a data typing
 * interface for files. Implementations of this class will
 * implement the getContentType methods which will derive a content
 * type from a file name or a File object. FileTypeMaps could use any
 * scheme to determine the data type, from examining the file extension
 * of a file (like the MimetypesFileTypeMap) to opening the file and
 * trying to derive its type from the contents of the file. The
 * FileDataSource class uses the default FileTypeMap (a MimetypesFileTypeMap
 * unless changed) to determine the content type of files.
 * 
 * @see javax.activation.FileTypeMap
 * @see javax.activation.FileDataSource
 * @see javax.activation.MimetypesFileTypeMap
 */

public abstract class FileTypeMap {

	private static FileTypeMap defaultMap = null;

	/**
	 * The default constructor.
	 */
	public FileTypeMap() {
		super();
	}

	/**
	 * Return the type of the file object. This method should
	 * always return a valid MIME type.
	 * 
	 * @param file
	 *            A file to be typed.
	 * @return The content type.
	 */
	abstract public String getContentType(File file);

	/**
	 * Return the type of the file passed in. This method should
	 * always return a valid MIME type.
	 * 
	 * @param filename
	 *            the pathname of the file.
	 * @return The content type.
	 */
	abstract public String getContentType(String filename);

	/**
	 * Sets the default FileTypeMap for the system. This instance
	 * will be returned to callers of getDefaultFileTypeMap.
	 * 
	 * @param map
	 *            The FileTypeMap.
	 * @exception SecurityException
	 *                if the caller doesn't have permission
	 *                to change the default
	 */
	public static void setDefaultFileTypeMap(FileTypeMap map) {
		SecurityManager security = System.getSecurityManager();
		if (security != null) {
			try {
				// if it's ok with the SecurityManager, it's ok with me...
				security.checkSetFactory();
			} catch (SecurityException ex) {
				// otherwise, we also allow it if this code and the
				// factory come from the same class loader (e.g.,
				// the JAF classes were loaded with the applet classes).
				if (FileTypeMap.class.getClassLoader() != map.getClass().getClassLoader())
					throw ex;
			}
		}
		defaultMap = map;
	}

	/**
	 * Return the default FileTypeMap for the system.
	 * If setDefaultFileTypeMap was called, return
	 * that instance, otherwise return an instance of
	 * <code>MimetypesFileTypeMap</code>.
	 * 
	 * @return The default FileTypeMap
	 * @see javax.activation.FileTypeMap#setDefaultFileTypeMap
	 */
	public static FileTypeMap getDefaultFileTypeMap() {
		// XXX - probably should be synchronized
		if (defaultMap == null)
			defaultMap = new MimetypesFileTypeMap();
		return defaultMap;
	}
}
